Thoracoscopy of pediatric patients has evolved from diagnostic lung biopsy to a myriad of both diagnostic and therapeutic procedures. In this chapter, we discuss those procedures related to the child's lung which are most commonly performed: lung biopsy; resection of bronchogenic cysts, pulmonary sequestrations, and pulmonary lobes; and the treatment of spontaneous pneumothorax.

Title

Pediatric Robotic Surgery: Lessons from a Clinical Experience.

Date

June 2007

Journal

Journal of Laparoendoscopic & Advanced Surgical Techniques. Part A

Excerpt

PURPOSE: Robotic surgery may improve minimally invasive surgery at high magnification by tremor filtration, motion-scaling, and improved dexterity with the provision of a wrist at the end of the robotic instrument. MATERIALS AND METHODS: We chose the Zeus Microwrist robotic surgical system as more applicable to small children than the competing da Vinci surgical system. We attempted 57 surgical procedures and completed 54. RESULTS: Completed procedures included Nissen fundoplication (n = 25), cholecystectomy (n = 18), Heller myotomy (n = 2), splenectomy (n = 2), Morgagni hernia repair (n = 2), and single cases of complex pyloroplasty in the chest, bowel resection, left Bochdalek congenital diaphragmatic hernia repair, esophageal atresia and tracheoesophageal fistula repair, and choledochal cyst excision. There were no complications related to the use of the robot. The mean time for the surgeon at the console using the robot was 117 +/- 39 minutes for Nissen fundoplication, and the total operating room time was 250 +/- 60 minutes. Surgeons found dissection, suturing, and knot tying easier than with conventional laparoscopy. None of the surgeons thought the lack of touch feedback (haptics) was crucial. CONCLUSION: Robotic surgery offers increased dexterity to the pediatric minimally invasive surgeon, but procedures require more time, and there is no defined patient benefit. The fact that robotic surgery digitalizes minimally invasive surgery creates exciting possibilities for training surgeons, planning operations, and performing surgery at great distances from the operator.

OBJECTIVES: To review the conservative management of pediatric renal trauma and investigate the significance of associated nonrenal injuries. METHODS: We performed a retrospective review of 63 pediatric patients with blunt renal injury who were treated expectantly. A comparison was made between operative and nonoperative management, mechanism of injury, treatment complications, requirement for blood transfusion, length of hospital stay, associated injuries, and incidence of pre-existing urologic conditions. RESULTS: The renal injury grade was grade I in 31 patients, grade II in 12, grade III in 8, grade IV in 10, and grade V in 2. Two patients underwent acute surgical exploration; one for nonrenal causes and one (2%) for life-threatening renal bleeding (grade V injury). Renorrhaphy was not performed, and 98% of patients were initially treated nonoperatively. Three patients (5%) underwent delayed renal surgery: one nephrectomy for Wilms' tumor, one partial nephrectomy for nonhealing grade IV injury, and one attempted repair of a renal pelvis injury with subsequent nephrectomy. Excluding 1 patient who died and one nephrectomy for tumor control, our renal salvage rate was 97% (59 of 61). The overall mean hospital stay was 7.7 days and was similar across all grades (grade I, 7.7 days; grade II, 7.8; grade III, 6.1; grade IV, 9.2; and grade V, 10.5 days). CONCLUSIONS: The results of our study have shown that pediatric patients with blunt nonexsanguinating renal injuries treated conservatively do well. The length of hospital stay did not increase with worsening severity of renal injury and, instead, was determined by the severity of the nonrenal associated injuries. This report adds to a growing body of published data that suggest that conservative management of pediatric blunt renal trauma is safe.

BACKGROUND: Minimally invasive pyeloplasty is a difficult procedure even for an expert laparoscopic surgeon. The major difficulty is associated with the limitations of intracorporeal suturing and knot tying. Surgical robots, which hold minimally invasive surgical instruments, have wrists and provide tremor filtration and motion scaling that might be expected to facilitate complex procedures in newborns. METHODS: Seven survival piglets (4.0-7.5 kg) underwent a totally minimally invasive robot-assisted unstented pyeloplasty employing the Zeus Robotic Microwrist System. The ureter was transected at the level of the ureteropelvic junction and 8 mm was resected. The unstented anastomosis was fashioned with running suture and intracorporeal knot tying. The animals were recovered and intravenous urography was performed at 1 month. After sacrifice, the anastomosis and the kidney were evaluated grossly and histologically for leak, caliber, and healing. RESULTS: All animals survived the procedure without postoperative complications. The mean robotic setup time was 19 minutes (range, 10-30 min), mean anastomosis time 51 minutes (range, 39-63 min), and mean total operation time 76 minutes (range, 57-87 min). The urography showed hydronephrosis in the first animal. The other 6 animals had no abnormalities. Histopathology demonstrated severe hydronephrosis in the first pig and moderate hydronephrosis in the sixth and seventh. All other animals had no sign of hydronephrosis. All anastomoses were well healed and intact. CONCLUSIONS: Robot-assisted laparoscopic pyeloplasty is a technically feasible procedure with acceptable morbidity in an animal model. The robotic technology enhances surgical dexterity and precision. Robotic assistance can increase the applicability of minimally invasive surgery to complex procedures in children.

Title

Laparoscopic Morgagni Hernia Repair in Children Using Robotic Instruments.

Date

February 2006

Journal

Journal of Laparoendoscopic & Advanced Surgical Techniques. Part A

Excerpt

BACKGROUND: Robotic surgery enhances minimally invasive surgery through tremor filtration, motion scaling, indexed movement, articulation, and improved ergonomics. We report 2 cases of computer- assisted, robot-enhanced, laparoscopic repair of Morgagni hernia in a 23-month-old weighing 10.2 kg and a 5-year-old weighing 21.6 kg. METHODS: Four 5 mm trocars were used to gain access to the abdomen. In the first case, standard laparoscopic instruments were used to dissect the liver from the rim of the defect and then reduce the hernia. In the second, robotic instruments were used for this dissection. In both cases, the robot- enhanced instruments were used to close the hernia defects with interrupted, nonabsorbable suture, using intracorporeal knot tying. RESULTS: Both cases were completed laparoscopically without a patch. The robotic system took 9 minutes to set up and drape. The average operative time was 227 minutes. The older child tolerated oral intake the day of surgery and went home the following day. The younger child tolerated oral intake and went home on postoperative day 2. CONCLUSION: Robot-assisted laparoscopic Morgagni hernia repair is feasible.

Title

Computer-assisted, Robot-enhanced Open Microsurgery in an Animal Model.

Date

September 2005

Journal

Journal of Laparoendoscopic & Advanced Surgical Techniques. Part A

Excerpt

BACKGROUND: Computer-assisted, robot-enhanced surgery improves laparoscopic and thoracoscopic surgery through tremor filtration, motion scaling, articulation, and improved ergonomics. Surgeons perform many open cases under magnification that magnifies the tremor present in all surgeons' hands, so the tremor filtration and motion scaling of robotic surgery may improve microsurgery. Our goal was to compare microvascular anastomoses performed with a robot-enhanced technique with a standard technique. METHODS: We performed end-to-end anastomoses in 1-mm rat femoral arteries with interrupted 10-0 suture. We compared the anastomotic time, patency, and leak rates between traditional microsurgery techniques (by hand) and a robot-enhanced technique using the Zeus robotic surgery system (Computer Motion, Goleta, California). The surgeon used an operative microscope for visualization in both techniques. RESULTS: We performed 30 anastomoses by hand and 31 with Zeus. We observed a remarkable degree of tremor filtration in the robot-enhanced cases. Anastomotic times for both techniques demonstrated a learning curve. Anastomoses done by hand (mean time, 17.2 minutes) were significantly faster than those done with Zeus (mean time, 27.6 minutes) (P = 0.0006). All anastomoses from both groups were patent, and none leaked after 3 minutes. CONCLUSION: The Zeus system is effective at performing complex, open, microsurgery tasks in vivo. There was no measurable benefit from the remarkable tremor filtration and motion scaling offered by robot-enhanced surgery.

Title

Robot-enhanced Fetoscopic Surgery.

Date

August 2005

Journal

Journal of Pediatric Surgery

Excerpt

BACKGROUND: Fetoscopic surgery carries with it less maternal morbidity than open fetal surgery. Robotic surgery facilitates endoscopic surgery through tremor filtration, motion scaling, indexed movement, articulation, and improved ergonomics. The goal of the authors was to explore using a robotic surgery platform in a fetal animal model. METHODS: Using the Zeus Robotic Surgery System (Computer Motion, Santa Barbara, CA), fetoscopic surgery in pregnant sheep was performed using a variety of techniques: uterus exteriorized or totally percutaneous and with liquid or gas insufflation. Using the percutaneous technique and gas insufflation, the authors created and sutured fetal skin and fascial defects. The ewes were recovered and killed 2 weeks postoperatively, and autopsies were performed on them and their fetuses. RESULTS: In the exteriorized uterus model, instrument movement was unpredictable and fluid leaked. In the fluid environment, clouding of the visual field and difficulty in immobilizing the fetus were major difficulties. In the survival model, 4 of the 6 fetuses survived to autopsy at 2 weeks and showed good healing grossly and histologically. CONCLUSIONS: The Zeus Robotic Surgery System can be used for fetoscopic surgery in a sheep model. The percutaneous approach with a nitrous oxide environment is the most effective. Advantages of robotic surgery may be applicable in fetoscopic surgery, but further work in a primate model is required.

BACKGROUND: Major enhancements offered by robotic surgery for minimally invasive procedure include tremor filtration, motion scaling, and the addition of a wrist to the instrument. Minor enhancements include indexing as well as safe and rapid instrument exchange. A benefit associated with any endoscopic procedure is magnification. It was hypothesized that these enhancements would allow the performance of complex gastrointestinal surgery. METHODS: Eight survival pigs (weight, 2.5-8 kg) underwent a robotically assisted minimally invasive portoenterostomy. The procedure was analogous to the Kasai portoenterostomy for biliary atresia usually performed for human patients at the age of 4 to 12 weeks. RESULTS: Five of the eight animals survived for more than 1 month after the operation, returning to normal eating and bowel habits in 2 to 3 days. None were jaundiced. All laboratory values were normal. At 1 month, the animals were killed. There was no anastomotic stenosis at either the end-to-side enteroenterostomy or the portoenterostomy. Histologically, the anastomoses were well healed. CONCLUSION: Computer-assisted robot-enhanced technology allows complex gastrointestinal surgery to be performed using minimally invasive techniques.

Title

Robotically Assisted Esophago-esophagostomy in Newborn Pigs.

Date

May 2005

Journal

Journal of Pediatric Surgery

Excerpt

PURPOSE: Repair of esophageal atresia and tracheoesophageal fistula (TEF) in the newborn is challenging when done as an open procedure but only a few surgeons have attempted this with minimally invasive surgery (MIS). Surgical robots that hold MIS instruments have wrists and provide tremor filtration and motion scaling, which might be expected to facilitate complex procedures in small spaces such as an esophageal anastomosis in a newborn. METHODS: Seven newborn pigs weighing 2 to 3 kg were used as a model. The authors performed an esophageal resection and end-to-end anastomosis using the Zeus Microwrist Robotic Surgical System. The authors monitored the following data-Zeus robotic set-up time, operating time, esophageal dissection time, and anastomosis time. After 1 month, the animals were anesthetized to perform esophagram and than were killed. RESULTS: In these very small animals the space available for performing an anastomosis is very limited, approximately 2 cm3. Two pigs each died 18 days postoperatively. One animal could not eat and died during esophageal dilation. The second pig died of unrelated enteritis. Neither had evidence of anastomotic leak at autopsy. The esophagram of the 5 pigs that survived for 30 days showed no narrowing or proximal dilation in 2. In 3 there was some stenosis requiring dilation. Histopathology was done on each operated animal. Two of the anastomoses were well healed, and 5 showed only focal small ulceration. CONCLUSIONS: Robotic assistance facilitates an MIS approach to the upper esophagus even in the limited space of the infant chest.

Title

Devastating Injuries in Healthcare Workers: Description of the Crisis and Legislative Solution to the Epidemic of Back Injury from Patient Lifting.

Date

May 2005

Journal

Journal of Long-term Effects of Medical Implants

Excerpt

The purpose of this report is to describe a crisis in healthcare, disabling back injuries in US healthcare workers. In addition, outlined is the proven solution of safe, mechanized, patient lifting, which has been shown to prevent these injuries. A "Safe Patient Handling--No Manual Lift" policy must be immediately instituted throughout this country. Such a policy is essential to halt hazardous manual patient lifting, which promotes needless disability and loss of healthcare workers, pain and risk of severe injury to patients, and tremendous waste of financial resources to employers and workers' compensation insurance carriers. Healthcare workers consistently rank among top occupations with disabling back injuries, primarily from manually lifting patients. Back injury may be the single largest contributor to the nursing shortage. Reported injuries to certified nursing assistants are three to four times that of registered nurses. A national healthcare policy for "Safe Patient Handling--No Manual Lift" is urgently needed to address this crisis. Body mechanics training is ineffective in prevention of back injury with patient lifting. Mandated use of mechanical patient lift equipment has proven to prevent most back injury to nursing personnel and reduce pain and injury to patients associated with manual lifting. With the national epidemic of morbid obesity in our country, innovative devices are available for use in emergency medical systems and hospitals for patient lifting and transfer without injury to hospital personnel. The US healthcare industry has not voluntarily taken measures necessary to reduce patient handling injury by use of mechanical lift devices. US healthcare workers who suffer disabling work-related back injuries are limited to the fixed, and often inadequate, relief which they may obtain from workers' compensation. Under workers' compensation law, healthcare workers injured lifting patients may not sue their employer for not providing mechanical lift equipment. Discarding healthcare workers disabled by preventable back injuries is an abuse which legislators must remedy. In addition, Medicare reimbursement policies must also be updated to allow the disabled community to purchase electrically operated overhead ceiling lifts. The US lags far behind countries with legislated manual handling regulations and "No Lifting" nursing policies. England and Australia have had "No Lifting" nursing policies in place since 1996 and 1998, respectively. The National Occupational Research Agenda (NORA) recognized a model in 2003 for reduction of back injuries to nursing staff in US healthcare facilities. Also in 2003, the American Nurses Association called for elimination of manual patient handling because it is unsafe and causes musculoskeletal injuries to nurses. The first state legislation for safe patient handling passed both houses in California but was vetoed by the Governor in September 2004. California and other states are preparing to (re)introduce legislation in January 2005. A national, industry-specific policy is essential to quell the outflow of nursing personnel to disability from manual patient lifting.

BACKGROUND/PURPOSE: Robotic surgery improves laparoscopic surgery through a more natural interface, tremor filtration, motion scaling, and additional degrees of freedom of the instruments. Here, the authors report that experience with robot-assisted fundoplication in children. METHODS: The authors have performed 15 laparoscopic fundoplications with the Zeus Robotic Surgery System and retrospectively reviewed prospectively collected data on set-up time, operating time, and outcome. RESULTS: All cases were completed successfully: one Heller myotomy with Dor fundoplication and 14 Nissen fundoplications. Patients ranged from 2 months to 18 years old (mean, 4.3 years) and from 3.4 kg to 37.7 kg (mean, 13.0 kg). There were no technical errors, equipment errors, or conversions. There were no complications in the first 30 days after surgery. The operating time declined from 323 minutes for the first case to 180 minutes for the last (mean, 195 minutes). The 14th case was the shortest at 123 minutes. Setting up the robotic surgery system took an average of 11 minutes. The surgeons perceived benefits of greater ease and confidence in suture placement and knot tying. CONCLUSIONS: The authors have successfully used surgical robots for gastric fundoplication at a pediatric teaching hospital. Our experience with this operation has shown the additional dexterity that the robot provides and will pave the way to more complex procedures.

BACKGROUND: Several changes occur during the transformation of normal tissue to neoplastic tissue. Such changes in molecular composition can be detected by Raman spectroscopy. Raman spectroscopy is a nondestructive method of measuring these changes, which suggests the possibility of real-time diagnosis during medical procedures. METHODS: This study seeks to evaluate the ability of Raman spectra to distinguish tissues. The Raman signatures of normal kidney, lung, and liver tissue samples from pigs and rats were characterized in vitro. Further, a human neuroblastoma and a hepatoblastoma, obtained at resection were also studied. RESULTS: The Raman spectra of the animal samples of kidney, liver, and lung are distinctly different in the intensity distribution of the Raman peaks. Further, the spectra of a given organ from pigs and rats, although similar, were different enough to distinguish between the 2 animals. In the patient tissues, the Raman spectra of normal liver, viable tumor, and fibrotic hepatoblastoma were very different. Fibrotic tissue showed a greater concentration of carotenoids, whereas viable tissue was rich in proteins and nucleic acids. The normal tissue showed both components. Similar differences were also seen in the neuroblastoma tissue. CONCLUSIONS: The results of this study show the potential use of Raman spectroscopy in clinical diagnosis.

Title

Robotics in Pediatric Surgery: Perspectives for Imaging.

Date

October 2004

Journal

Pediatric Radiology

Excerpt

Robotic surgery will give surgeons the ability to perform essentially tremorless microsurgery in tiny spaces with delicate precision and may enable procedures never before possible on children, neonates, and fetuses. Collaboration with radiologists, engineers, and other scientists will permit refinement of image-guided technologies and allow the realization of truly remarkable concepts in minimally invasive surgery. While robotic surgery is now in clinical use in several surgical specialties (heart bypass, prostate removal, and various gastrointestinal procedures), the greatest promise of robotics lies in pediatric surgery. We will briefly review the history and background of robotic technology in surgery, discuss its present benefits and uses and those being explored, and speculate on the future, with attention to the current and potential involvement of imaging modalities and the role of image guidance.

Title

Traumatic Hematuria in Children Can Be Evaluated As in Adults.

Date

February 2004

Journal

The Journal of Urology

Excerpt

PURPOSE: Controversy exists regarding whether children who present with blunt abdominal trauma and microhematuria should undergo renal imaging. Adult blunt trauma victims who present without gross hematuria, shock, or significant deceleration or other major associated injuries do not require renal imaging. This study was designed to evaluate whether the criteria for imaging the renal parenchyma in adult blunt trauma victims apply to the pediatric population. MATERIALS AND METHODS: We retrospectively reviewed 720 consecutive pediatric patients with suspected renal trauma to determine mechanism of injury, evaluation and treatment of subsequent injuries. RESULTS: Of the 720 trauma patients with hematuria (mean age 8 years) 334 underwent imaging, and 59 renal injuries were identified (grade I 32, grade II 6, grade III 8, grade IV 12, grade V 1). A total of 11 patients underwent exploration, resulting in 3 nephrectomies (grade IV 2, grade V 1). Renorrhaphy was not necessary and all other cases were managed conservatively. All patients with significant renal injuries experienced either gross hematuria, shock (systolic blood pressure less than 90 mm Hg) or a significant deceleration injury. CONCLUSIONS: The decision to image pediatric trauma cases based on the adult criteria of gross hematuria, shock and significant deceleration injury is appropriate. Among 720 pediatric cases of potential renal injury all would have been identified.

Title

Robotic Surgery: an Update.

Date

January 2004

Journal

Journal of Long-term Effects of Medical Implants

Excerpt

Minimally invasive surgery techniques have revolutionized surgery. Robotic surgery may be the next revolution in surgical technology. Robotics coupled with minimally invasive surgery and microscopic surgery provides the potential to do more complex and more precise tasks. Robotic surgery offers tremor filtration, motion scaling, indexed movements, additional degrees of freedom, and improved ergonomics. We explore robotic history, the present surgical technology, the current clinical cases and research, and the future of robotics. We will look specifically at the birth and progress of our own problem.

Title

Anterior Bridging Bronchus.

Date

April 2003

Journal

Pediatric Pulmonology

Excerpt

Previously reported patients with a bridging bronchus (BB) presented with respiratory distress. In addition, each patient had one or more associated anomalies. All but two patients progressed to cardiopulmonary failure and death. We describe a case of an anterior BB without associated anomalies, who did well without operative intervention. This patient presented with a cough at 6 months of age. Chest X-ray was normal, but due to suspicion of foreign body aspiration, bronchoscopy was performed, which revealed a third bronchus at the carina. Bronchography demonstrated the anatomy of the BB. The patient has continued to do well without further intervention.

Title

Three Quantitative Approaches to the Diagnosis of Abdominal Pain in Children: Practical Applications of Decision Theory.

Date

December 2001

Journal

Journal of Pediatric Surgery

Excerpt

BACKGROUND/PURPOSE: The authors compared 3 quantitative methods for assisting clinicians in the differential diagnosis of abdominal pain in children, where the most common important endpoint is whether the patient has appendicitis. Pretest probability in different age and sex groups were determined to perform Bayesian analysis, binary logistic regression was used to determine which variables were statistically significantly likely to contribute to a diagnosis, and recursive partitioning was used to build decision trees with quantitative endpoints. METHODS: The records of all children (1,208) seen at a large urban emergency department (ED) with a chief complaint of abdominal pain were immediately reviewed retrospectively (24 to 72 hours after the encounter). Attempts were made to contact all the patients' families to determine an accurate final diagnosis. A total of 1,008 (83%) families were contacted. Data were analyzed by calculation of the posttest probability, recursive partitioning, and binary logistic regression. RESULTS: In all groups the most common diagnosis was abdominal pain (ICD-9 Code 789). After this, however, the order of the most common final diagnoses for abdominal pain varied significantly. The entire group had a pretest probability of appendicitis of 0.06. This varied with age and sex from 0.02 in boys 2 to 5 years old to 0.16 in boys older than 12 years. In boys age 5 to 12, recursive partitioning and binary logistic regression agreed on guarding and anorexia as important variables. Guarding and tenderness were important in girls age 5 to 12. In boys age greater than 12, both agreed on guarding and anorexia. Using sensitivities and specificities from the literature, computed tomography improved the posttest probability for the group from.06 to.33; ultrasound improved it from.06 to.48; and barium enema improved it from.06 to.58. CONCLUSIONS: Knowing the pretest probabilities in a specific population allows the physician to evaluate the likely diagnoses first. Other quantitative methods can help judge how much importance a certain criterion should have in the decision making and how much a particular test is likely to influence the probability of a correct diagnosis. It now should be possible to make these sophisticated quantitative methods readily available to clinicians via the computer.

Title

Bile Duct Size Does Not Predict Success of Portoenterostomy for Biliary Atresia.

Date

October 2000

Journal

Journal of Pediatric Surgery

Excerpt

BACKGROUND/PURPOSE: Presence of large bile ducts (>200 microm) at the portal end-plate has been suggested to predict success after portoenterostomy. The authors reviewed their patients with biliary atresia to test the hypothesis that bile duct size in patients with successful portoenterostomy was no different than in the patients with unsuccessful portoenterostomy. METHODS: The authors reviewed the patients at their institution from 1989 to 1998 who had the diagnosis of biliary atresia (n = 38). A pathologist blinded to the results of the operation confirmed the measurements of the bile duct remnants. RESULTS: Five of the 38 patients did not have a portoenterostomy. They underwent cholangiogram and liver biopsy and were evaluated for liver transplantation. All patients who underwent surgery (n = 33) had a Roux-en-y hepaticojejunostomy. Twenty-one patients had successful surgery (64%) and 12 patients (36%) had unsuccessful surgery. The average age at operation in the successful group was 50.9 +/- 3 days and in failures, 57.9 +/- 4 days (P = .16). Duct size at the portal end-plate was not different between the successes and failures. Two of the patients in the success group had no evidence of bile ducts grossly or histologically. CONCLUSION: Children presenting early in infancy (<3 months) with biliary atresia should undergo a portoenterostomy regardless of the size of the bile ducts at the time of exploration.

BACKGROUND. The success of coronary revascularization for ischemic cardiomyopathy (left ventricular ejection fraction of 0.25 or less) has been unpredictable. We and others have demonstrated that the hospital operative mortality rate for these operations has been surprisingly low, particularly if evidence of ischemia is present. We subsequently liberalized our selection criteria based on our hypothesis that coronary artery bypass grafting is safe in this subset of patients regardless of the status of their distal coronary vasculature. METHODS. To examine this hypothesis, we studied retrospectively our patients undergoing coronary artery bypass grafting from 1983 to 1993. Ninety-six patients with ejection fractions of 0.25 or lower underwent this operation, with 88 hospital survivors (mortality 8%). All of the patients had clinical symptoms of heart failure. The male to female ratio was 4.6:1. The average age was 63.1 +/- 0.9 years (mean +/- standard error of the mean). Patients were excluded if they had valvular heart disease other than mild to moderate mitral regurgitation, required resection of a ventricular aneurysm, or required an emergency operation for acute coronary occlusion. Possible predictors of death were examined retrospectively. The catheterization films were reviewed retrospectively by a cardiovascular surgeon who was blinded to patient outcome and was never involved in the clinical management of any of the patients. Vessel quality was described as good, fair, or poor. RESULTS. Increased age and poor vessel quality were the only significant predictors of poor outcome. Sex, presence or absence of angina, preoperative angina, preoperative ejection fraction, preoperative arrhythmia disorder, aortic cross-clamp time, and the number of bypass grafts had no significant effect on outcome in the perioperative period. CONCLUSION. These results demonstrate that poor vessel quality and older age are predictors of poor outcome in patients with low ejection fractions undergoing myocardial revascularization. We conclude that poor distal coronary vasculature is a contraindication to coronary artery bypass grafting in patients with an ejection fraction of 0.25 or less, even if angina is present.

Title

Pulmonary Function After Non-heart-beating Lung Donation in a Survival Model.

Date

August 1995

Journal

The Annals of Thoracic Surgery

Excerpt

BACKGROUND. Lung procurement from recently deceased cadavers has been suggested to enlarge the limited donor pool. We hypothesized that lungs harvested from non-heart-beating donors (NHBD) would function as well as those harvested from heart-beating donors. METHODS. Sixteen adult swine underwent left lung allotransplantation. Controls received lungs procured from heart-beating donors, NHBD pigs received lungs immediately harvested from donors after death from asphyxiation, and NHBD-15 and NHBD-30 pigs received lungs harvested after 15 and 30 minutes after asphyxiation. RESULTS. After 1 week of survival, mean dynamic airway compliance (mL/cm H2O +/- standard error of the mean) was 16.3 +/- 0.7 in controls, and 17.3 +/- 1.0, 16.4 +/- 6.0, and 7.3 +/- 1.6 in the NHBD, NHBD-15, and NHBD-30 groups, respectively (p = 0.02, NHBD-30 versus others combined). No significant differences were noted in the pulmonary venous partial pressure of oxygen or pulmonary vascular hemodynamics compared with controls. CONCLUSIONS. The decrease in airway compliance noted in the NHBD-30 group may reflect an exacerbation of reperfusion injury caused by 30 minutes of warm ischemia during organ retrieval. We conclude that posttransplantation lung function using an NHBD with up to 15 minutes of warm ischemia is equivalent to lung function after heart-beating harvest.

Title

Prevention of Spinal Cord Injury After Repair of the Thoracic or Thoracoabdominal Aorta.

Date

February 1995

Journal

The Annals of Thoracic Surgery

Excerpt

Spinal cord injury occurring as the result of surgical repair of thoracic and thoracoabdominal aortic disease remains a devastating complication. The incidence of postoperative neurologic deficits varies from 4% to 38%. Factors associated with a greater risk for injury include the presence of dissection or extensive thoracoabdominal disease, and a prolonged cross-clamp time. Spinal cord ischemia initiates a deleterious cascade of biochemical events that ultimately result in an increased intracellular calcium concentration. Calcium-activated proteases, lipases, and nucleases mediate the processes that cause cell injury. The accumulation of oxygen-derived free radicals and the occurrence of hyperemia during reperfusion are also contributing causes of spinal cord injury. Increasing the spinal cord blood flow with shunts, oxygenated bypass circuits, cerebrospinal fluid drainage, the intrathecal administration of vasodilators, and the reattachment of intercostal arteries has been tried in an effort to increase spinal cord perfusion. Pharmacologically based measures to prevent spinal cord injury have been pursued, and these have consisted of hypothermia, anesthetic agents, calcium channel blockers, free radical scavengers, and immune system modulation. However, no single technique has proved to be consistently effective in preventing ischemia-induced spinal cord injury.

Title

Compensatory Growth of Porcine Right Lungs After Chronic Rejection of Transplanted Left Lungs.

Date

February 1995

Journal

The Annals of Thoracic Surgery

Excerpt

Neonatal lung hypoplasia is frequently a fatal condition often associated with congenital diaphragmatic hernia. Unilateral lung transplantation rarely has been performed for this indication, although it is a potential solution. It is not known whether the transplant needs to function permanently or to act as a bridge until the native lung develops. It is also not known whether the native lung will grow in the face of an immunosuppressed state and chronic rejection of the transplanted lung. We therefore developed a porcine model of left lung rejection to study this. Infant swine underwent left lung transplantation. Chronic rejection occurred in all, resulting in nonfunction of the transplanted lung. The right lungs of these animals were compared with the right lungs of size-matched and age-matched control animals not given immunosuppressive treatment and not undergoing transplantation. There were no differences in terms of the functional residual capacity, airway compliance, and airway resistance among the groups. There was a significant increase in the pulmonary vascular resistance in the animals with transplanted lungs. There was also a significant increase in the lung weight in these animals. Unilateral pneumonectomies were done in 4 infant pigs to serve as controls. Three of the 4 did not survive the operation because of acute pulmonary failure. In conclusion, the study group exhibited evidence of compensatory growth that was not seen in the control animals, as shown by the increase in lung weight. This suggests that contralateral lung growth occurs in a growing animal, despite the effects of immunosuppression therapy and chronic rejection of the transplanted lung.

Title

Ambulatory Intraaortic Balloon Counterpulsation.

Date

November 1994

Journal

The Annals of Thoracic Surgery

Excerpt

A technique is described for the retroperitoneal placement of a balloon pump that preserves patient mobility. This technique may be superior to standard femoral placement when prolonged support is required for cardiac transplant candidates awaiting donor organs.

Title

Management of Renal Tumors Involving the Inferior Vena Cava.

Date

October 1994

Journal

Journal of Vascular Surgery : Official Publication, the Society for Vascular Surgery [and] International Society for Cardiovascular Surgery, North American Chapter

Excerpt

PURPOSE: We reviewed our experience of the resection of renal tumors involving the inferior vena cava (IVC) from 1987 to 1992 with the hypothesis that retrohepatic IVC involvement of renal tumors can be managed without cardiopulmonary bypass (CPB) and circulatory arrest with acceptable morbidity and mortality rates. METHODS: We retrospectively reviewed our experience of radical nephrectomies for renal tumors from 1987 to 1992 (n = 69). Of these, 13 had involvement of the IVC (19%). Three of the patients had right atrial extension requiring CPB with circulatory arrest. Three patients had retrohepatic involvement, and seven had infrahepatic involvement. All thirteen patients underwent operative removal of the tumor and tumor thrombus. RESULTS: The patients with atrial extension who were treated with CPB and circulatory arrest had hospital and 1-year survival rates of 100% (three of three). The patients with retrohepatic extension treated without CPB and circulatory arrest had hospital and 1-year survival rates of 100% (three of three). The patients with infrahepatic extension treated without CPB and circulatory arrest had hospital and 1-year survival rates of 85% (six of seven) and 50% (three of six), respectively. There was no statistically significant difference between groups. The hospital death occurred in a patient who had a massive pulmonary embolism and disseminated intravascular coagulation before operation. The deaths that occurred before 1 year were due to metastatic disease and unresectable disease at the time of operation. CONCLUSION: CPB with circulatory arrest is not required in patients with retrohepatic IVC extension of renal tumors, and aggressive resection can be performed in these patients with acceptable morbidity and mortality rates.

Title

Successful Use of Undersized Donors for Orthotopic Heart Transplantation--with a Caveat.

Date

July 1994

Journal

The Annals of Thoracic Surgery

Excerpt

Accepted clinical practice has been to require body weights to be within 20% as a criterion for matching donor to recipient for cardiac transplantation. From November 1989 through September 1993 we began accepting larger differences in body weight between donor and recipient with 80 orthotopic heart transplants performed. Twenty-eight of these transplants used undersized donors (donor-to-recipient body weight ratio [DRBW] of 0.6 to 0.8) with the remaining donors being either size matched (DRBW = 0.8 to 1.0) or oversized (DRBW > 1.0). Thirty-three of the 80 transplant recipients (41%) were classified preoperatively as United Network for Organ Sharing (UNOS) status I and the remaining patients were classified as UNOS status II. Hospital survival for status I recipients was 9 of 14 (64%) for undersized donors, 7 of 8 (87.5%) for sized-matched donors, and 11 of 11 (100%) for oversized donors (p < 0.05). Hospital survival for status II recipients was 12 of 14 (85.7%) for undersized donors, 24 of 24 (100%) for sized-matched donors, and 8 of 9 (88.8%) for oversized donors. Our data support the continued use of hearts from undersized donors in status II recipients. The use of hearts from undersized donors in status I recipients is associated with increased mortality compared with size-matched donors and must be undertaken with caution.

OBJECTIVE: The authors ascertained the optimal timing of repair of an abdominal aortic aneurysm (AAA) after coronary artery revascularization. SUMMARY BACKGROUND DATA: Cardiac events are the most common cause of death after elective repair of AAA. Preoperative coronary revascularization has significantly reduced postoperative cardiac complications after elective AAA repair. Currently, most patients undergo repair of asymptomatic AAA within 6 months after the coronary revascularization. METHODS: The authors performed a retrospective review of patients who underwent repair or scheduled repair of an asymptomatic AAA within 6 months after coronary artery bypass graft (CABG) between March 1988 and October 1993. RESULTS: There was no mortality in the group of patients (n = 14) who underwent repair of AAA simultaneously or within 14 days of coronary revascularization. In contrast, there was a significantly increased mortality rate of 3 of 9 (33%) in patients scheduled to undergo repair of the AAA more than 2 weeks after coronary revascularization (p < 0.05). All nonsurvivors died between 16 and 29 days after CABG, and died as a result of ruptured AAA. CONCLUSION: Elective AAA repair should be undertaken simultaneously or within 2 weeks of coronary artery revascularization because of an increased risk of postoperative AAA rupture seen after this time period. In addition, simultaneous or early postoperative AAA repair does not increase the overall operative risk.

Spinal cord injury after operations on the descending thoracic and thoracoabdominal aorta remains a persistent clinical problem. Previous attempts to decrease the risk of this devastating complication by lowering the rate of metabolism of the spinal cord have met with varying success. We hypothesized that the tolerance of the spinal cord to an ischemic insult could be improved by means of adenosine. Twenty New Zealand white rabbits underwent 40 minutes of isolated infrarenal aortic occlusion after heparin anticoagulation. Clamps were placed both below the left renal vein and above the aortic bifurcation. In 10 rabbits (group A), a bolus of adenosine (100 mg) was infused into the isolated aortic segment immediately after crossclamping and this bolus was followed by a flush of hypothermic saline (8 degrees C, 30 ml/kg) over the first 10 minutes of ischemia. In one control group of five animals (group B), the descending infrarenal aorta was crossclamped without infusion of adenosine or saline. In another control group of five animals (group C), the aortic segment was flushed with normothermic saline (37 degrees C) in a fashion identical to that of the study group. The aortic clamps were removed after 40 minutes, the abdomen was closed, and the animals were allowed to recover from anesthesia. Spinal cord function was assessed 12, 24, 48, 72, and 96 hours after operation by the Tarlov scale. All animals were put to death at 96 hours after operation and spinal cords were harvested for histologic analysis. The spinal cord function of all group A animals was fully intact with Tarlov scores of 5; group B and group C animals were all paraplegic with Tarlov scores of 0 (p < 0.001, general linear models analysis of variance). Histologic examination of spinal cords from group A rabbits revealed no evidence of cord injury, whereas spinal cords from groups B and C had evidence of extensive cord injury with central gray necrosis, axonal swelling, dissolution of Nissl substance, and astrocyte and macrophage infiltration. Regional infusion of the crossclamped infrarenal rabbit aorta with hypothermic saline and adenosine completely prevented paraplegia in our model despite a 40-minute ischemic insult.

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